Lecture 22

Question 1

Communities:

Answer 1

a collection of species in the same area that may interact

Question 2

Determinants of the composition of Bird communities

Answer 2

1. special pool “what species are there” 2. resources 3. assembly rules (competition)

Question 3

species pool is a function of ——- and ——–

Answer 3

speciation and biogeographt

Question 4

a fundamental concept in ecology is that different species must have different water to co-exist?

Answer 4

niches

Question 5

Food resources- comparisons between temperate and tropical forest avifaunas indicate what?

Answer 5

1. many tropical species use resources which are not so available in temperate forests (fruit, nectar, large insect) 2. large numbers of similar species can co exist in the same areas of tropical forest 3. Many species have narrowly defined niches 4. The floristic and structural diversity of tropical forests provides a greater variety of microhabitats

Question 6

structural complexity of vegetation increase number of what?

Answer 6

microhabitats. More structural complexity in tropical forests than in temperate forests, more bird species

Question 7

what does this image tell you?

Answer 7

some opportunities were not avilable in temperate

Question 8

niches can be based on several types of resources but the 2 main ones are?

Answer 8

1. food
2. nest sites

Question 9

Guilds:

Answer 9

these are groups of species that exploit the same class of environmental resources in a similar way

Question 10

3 use of guilds in research questions?

Answer 10

1. among guild comparisons
2. within-guild analyses
3. generally, used for broad scale comparisons between structure of communities when it is too time consuming to analyze each species individually and you are more interested in how the communities are functioning

Question 11

differences within the foliage gleaning insectivores guild in oak woodland california. They looked at how much they hawked and how much they gleaned. These attributes didnt seperate the species all that well. What does this show?

Answer 11

shows that niches aren’t partioned on a single factor (considerable overlap between some species)

Question 12

assembly rules:

Answer 12

interactions between species affect which species are present. For birds, the primary form of interaction is competition

Question 13

3 pieces of evidence of competition:

Answer 13

1. ecological isolation of sympatric species
2. Competitive release
3. Character displacement

Question 14

Character displacement:

Answer 14

shift in morphology (bill for example) as the niche expands and contracts in response to the absence or presence of competitors

Question 15

are communities stable?

Answer 15

often not stable

Question 16

how does forest structure change once you cut it?

Answer 16

Not mixed anymore! Either get more pine or more aspen!

Question 17

Logging has the most effect on what kind of birds?

Answer 17

cavity nesting birds and woodpeckers!